2008 MacBookPro-not booting

I know the battery needs servicing, however whenever I turn on my internet it is connected to power and the green light was on.



I am getting this message: "No bootable devices -- insert boot disk and press any key".



I have tried two different bootable usb keys. Also a Snow Leopard installation CD.

When I press "any key" - nothing happens.



Anyone have any advice?



I do have a much newer MBP but I am curious as to why this happened.

via ehMac.ca http://ift.tt/1DwNjA8